1. Field of the Invention
The present invention relates to miniature multi-position return to center potentiometers.
2. Description of the Prior Art
Rotary potentiometers that return to their center position after being displaced are well known. Typically, a ball held in position by a spring encounters one or more detents. When the necessary torque is applied to the potentiometer shaft, the ball is forced out of a detent and the shaft is rotated to next the desired detent. When the shaft is released, a return spring provides the necessary torque to force the ball out of the detent and return the shaft of the potentiometer to its center position detent. In the typical configuration, the torque required from the return spring must be of the same general magnitude as the torque required to rotate the shaft from its center detent position.
In those applications where the space available for the potentiometer is severely limited, such as in aircraft instrument panels, the return spring cannot be made large enough to generate the required torque to return the potentiometer to its center position. Making the detents smaller so as to require less torque from the return spring is generally unacceptable. The knowledge of the position of the potentiometer imparted by the positive feel of the detent is an essential part of its function. The present invention provides a detent configuration that permits the use of a very small return spring while retaining the needed positive feel of each detent.